How to set the background image of a menu item?

[Sydonian]

I'm trying to set the background image of a item in VerticalMenu, and I find two properties "SelectionBackground" and "SelectionHoverBackground", but after testing I found that "SelectionBackground" only works when the menu item is pressed.

So is there a way to set the background when the item is not hovered or pressed?

ps: the "SelectionBackground" seems better to be "SelectionPressBackground"